Coincidence-telemeter.



O. BPPENSTEIN.

GOINGIDENGE TELEMETER.

APPLICATION FILED NOV'.15, 1912.

1 0745 935; Patented Oct. 7,1913;

2 SHEETS-,SHEBT 1.

0. EPPBN STEIN.

- COINGIDENCE TELEMETER.

' 2SHEETSSHEET 2.

tors, in the total image-'fieldof which'threev 4 warren-snares earner nutrien- OTTO nrrnusrnm, on anus, GERMANY, ASSIGNOR "to THE FIRM or CARL miss, one

- JENA, GERMANY.

COINCIDENCE-TELEMETER.

Specification of Letters Patent.

Application filed November 15, 1912. Serial No. 731,602.

,T 0 all who-m it may concern Be it known that l, OTTO EPPENSTEIN, a citizen of the German Empire, residing at Jena, Germany, have invented a new and useful CcincidenceTelemeter,of which the v fol-lowing is a specification.

. The invention relates to uniocular telemesingle image-fields follow one upon the other in a direction perpendicular to that of the base-line. The two outer singleimagefields are each filled by an erect image, the inner one contains an 1mage,.which 1s contiguous to one of the said erect images in a straight line, the contiguous images belonging to opposite ends of the base-line and having such a relative position in the height direction, that their-common boundary-line isa line of coincidence. While it is immaterial in applying the invention, whether the baseline is vertical or horizontal, it is in the following always assumed to be horizon tal. Similarly the assumption, which is cer' tainly not essential but still convenient in applying the invention, shall be made, that the-inner single image field extends in the form of a, band across the entire field of vis i,on.

Assuming in the wellknown telemeter that one ofthe two images filling the outer single image-fields, which lies as viewed from the line of coincidence beyond the middle single-image-field, as being produced. through this latter single image-field, it would containin the line of coincidence the,

same object-points as the image filling the outer single image-field on the near side of the said middle single image-field (the terms F remote and near are hereinafter used, for the sake of brevity, to indicate the positions just described) there would therefore correspond to that one of its. imagelines, which would coincide with the line of coincidence, in the other image an imageline, which also coincides with the line of coincidence. In these two erect images taken together, to which in the following the term outer images is applied, a piece is missing, viz. that corresponding to the inner single image-field. When this single image-field is filled by an erect image, the latter certainly contains the missing piece, all the same the clear'ness is disturbed by parts of this image being displaced in a direction parallel to that of the base-line rela tively to the outer images. When the inner single image-field is filled, as is usually the case, by an image inverted perpendicularly to the direction of the base-line, the piece missing from the outer images does not ap pear in the image-field at all. In order to remove this disturbance of the clearness by the inner image independently of the height of the inner single image-field, according to the present invention the outer single image-field, which is not contiguous to the line of coincidence, is filled by an image, which is so constituted, that to that one of its image-lines, which, on this image being produced through the inner single image-field, would coincide with the line of coincidence, in the other outer image there corresponds an image-line at a distance from the line of coincidence, which is at least equal to the heightof the inner single image- Patented Oct. EH31.

There thenappears in the remote outer single image-field at least that piece,

field of vision in the remote image may be Y enlarged, without prejudicing the accuracy i of measurement in the near one, by giving the" said remote image a less magnification.

.This enlarged field of vision may then be utilized, especially when in it the zone, which is contiguous to the line of coincideuce, is repeated, like the, field oi vision of a finder telescope.

Those telemeters, the inner single imagefield of which is filled by a single inverted image, have in all those cases, in which the V a outer mages taken together are without a gap, the special advantage, that almost 'ior every object the lower and upper limiting line of the said single image-field may each act equally well as the line of coincidence.

Only for an object, in'which exclusively an extremity at its upper or lower end respectively is suitable for measuring purposes, the lower or the upper position respectively of the line of coincidence would be proferable.

' In that form of the well-known tclemcter, in which the inner single image-field is filled the outer images by twice the height of @n examining the matter "more displacementbesides the inner image-onlythat outer image need take part, the limiting line of. which is to become through the change ,a line of coincidence. the remot/e outer image is disposed according to the" present invention, tlns relative displace- -alrea dy partly effected tromthe first; For,

meat of the remote outer in age andthe' iner one may, when the niagnifimtion is equal in the total image-field, he considered as the change of the line of coincidence it is then only necessary to supplement the rela-' live displacement so far as to become equal to double the height of the inner single image-field. The more the remote outer image is from the first disposed in a displace d'position, the smaller is the relative displacement still required-for the change of the lineot coincidence. 'lhereis only required 6.. 9., when'the' remote outer image is so disposed that there corresponds to its boundary-line in the other oater image the line of coincidence, when the said former image maytherefore be regarded as hemg from thefirst displaced, as compared with its position in the well-lmown telemeter, by a v the height of the .inner single image-field, for

changing the line of coincidence a further relative displacement by the single height of the inner single image-field. When the two outer images are disposed in their relative position in such a manner that to the boundary-line-of one of them'there corre-' sponds in the other one an image-line, which has from the boun'darydine of the latter a distance equal to the height of the inner sinline.

gle imagefield, no further relative displacement at all is required for changing the line of coincidence, both limiting lines of the inner single itna'ge-field-loeing from, the first lines of coincidence.

The two outer images may both belong to the same orto opposite ends of the base- When both outer images are made to helong to the same end, a relative position as to height corresponding to the invention of corresponding image-lines of the outer inaages may be eficcted by a retracting prisinor by two such prisms, e. g. by placing in front of the image-plane in the path of the ray-pencil-systern, from which two outer images are formed, a pair of such retract-ing IISIHS, the refractlng edges of which are 1n cont-act with each other. By this means the two parts of the raypencil-system, which furnish the two outer images are made divergent, so that these images find themselves moved apart, In a separating pnsin system I g; "in". these images are then combined hose-line of the sihgleQ either directly, or with the help on o of lenses of reversion snch man?- ner that this filling comes to lie between there may also be employed for causing the divergence two reecting surfaces, which are deflection of the two parts of the pencil-systom.- lPhe divergence of -the 'two'parts of the pencil-system may he totally or partially neutralized by further refraction or reflecsystem. The separating prism system can by refraction or reflection, and the separatthe divergence,

\ll hen both the onterfirnages are to belong to the'saroe end of thehase-line, a filling of the image-fielda'corresponding to the invention, may also he obtained by disposing at that end of the baseline, to which the a two outer images belong, instead of one objective lens two objective part lenses, the optical "axes of which lie parallel to each other in a plane perpendicular to the plane of triangulation. The images, which are formed by these part-lenses and-lie moved apart, are. then united in a separating prism system with the belonging to the other end out t e hase-line'of the, inner single image-field insuch amanner that this filling comes to lie between them.

- A substantially difierent methodcomplying with the invention, in which method the outer images may belong to the same or'to opposite endsot" the base-line, is the following one: lln a separating prism systern in .the first place two douhle images are formed from the ray-pencil-systems belonging to the two'ends of the base-line. These two double images, one or the other of prodnct of the otherwise lost rays, are then presented to the ocular consists of two prin cipal parts, one of which proceeds from one of the double images and contains one of the outer images and the other of which contains the other enter image.

in the annexed drawing: Figures 1 to 4 each show the total imagefield presented by a telenieter accordin to the invention, the inner single imagelield of which said total image-field is filled by an image inot the hose-line- Figs. 5 and 6 show in elevation and plan respectively the. optical system of a constructional example oi the telemeter according to the invention. Fig.

livith the inclined to each other, with which arrangenoent there is combined a common greater tion before entering: the separating prisming surfaces canhe so disposed as*-to new united in such a manner that the total image vetted direction perpendicular to that themk In place oi the retracting itselllje so formed as to cause the divergence which may optionally he regarded as-tlie proceeds from the other'donlole-iniage and and plan respectively the optical systemv r ofa t-hird form of the telemeter, presenting a total image-field corresponding to that shown in Fig. 4. Fig. 13 is a section on an enlarged scale along line 1313 of Fig. 12 through the separating prism system of this telemeter. Figs. 14 and 15' show in elevation and planrespectively the optical system of afourth form of thetelemeter, hav ing two separating prism systems and presenting a total image-field corresponding to Fig.1. Fig. 16 is an enlarged front elevation of one 'ofthe separating prism systoms of this telemeter. Fig. 17 shows another forn; of this system, to which a. total image-field such as that shown in Fig. 2 corresponds. Figs. 18 and 19 show a third form of this system and the total imagefield corresponding to it respectively. Fig.

' 20 shows a total image field corresponding to another modification of the separating prism system of Fig. 18.

In Figs. 1 and 2 the inner single image field is bounded-by the line of coincidence a and by a line 5 parallel to a, the line of coincidence forming in Fig. 1 the lower boundary of the said image-field and in Fig. 2 its upper boundary. The remote erectimage has the same magnification as the other images and is so disposed that to that one of its image-lines, which on this image being produced through the inner single image-field would coincide with the line of coincidence, there corresponds in the near erect image an image-line, the distance of which from the line of coincidence is equal to the height of the inner single imagefield. Therefore in Fig. 1 the two outer single image-fields together show the sailing boat without any portion missing, and the horizon and a steamer have come insight. In Fig. 2 the sailing boat as seen in the two outer single image-fields together is also complete.

In Fig. 3 also the same magnification oh- I tains throughout the total image-field. The

relative position as .to height of the two erect images is such that in each of these two images the distance of that image-line, which-corresponds to the boundary-line of the other image, from its boundary-line is equal to the height of the inner single image-field. The relative position as to height of the two erect images on the one there is coincidence simultaneously between each of the contiguous images. Either of the two lines of coincidence may optionally be used for the purpose of measurement.

In Fig. 4:.the upper erect image is of smaller magnification and so disposed that the zone, with which the lower erect image is contiguous to the line of coincidence a, is repeated above the upper limiting line b of the inner single image-field. Through the enlargement of the field of vision beside the object to'be measured a third vessel and thecoast have become visible. The dotted lines, which maybe taken as corresponding to lines of demarcation disposed in the focal plane of the ocular, serve for indicating that piece of the upper erect image, which corresponds to the piece of the lower erect image recurring in the said upper image.

The telemeter in Figs; 5 and 6 has the same magnification throughout the total image-field. The inner single image-field is filled by an inverted image belonging to the left-hand end of the base-line and the outer images belong to the right-hand end of the baseline. By means of two retracting prisms, 0, c, which are'contiguous with their retracting edges, the two parts of the pencil-system, giving the upper and lower outer image respectively, are rendered divergent. In the intermediate zone arising from the moving apart of these two images there lies a production of each image, becoming constantly less luminous. In the middle of the intermediate zone, where both productions are of equal luminosity, the

ing device. The objective prisms f are disaosed as the foremost members of the sys tem. By means of a collective lens which is cemented together with the double prism 0, and a lens of reversion the images belonging-to the right-hand end of the base-line are imaged in a separating prism system k if. Similarly the image belonging to the left-hand end of the baseline is imaged by means of a collective lens 7 and a lens of reversion 7 The separating layer h" is divided into two parts; hence it presents two separating edges, as may be seen from the section along the separating layerof the separating prism system lt fhtin Fig. 7. According as the inverted imageis adjusted in the height direction the lowenor upper limiting line of the inner single image-field may serve as the line of coincidence. A Ramsden ocular is indicated by the two lenses 6 and i Ac-' cording as the two erect images areadjusted .with regard'to their relativeposition as to height, either' the missing piece ofthese images can be recovered as in Figs. 1 and 2 or, when the above mentioned intermediate zone is made partially visible, on the side remote from the inverted image in the first place a repetition of the zone contiguous to I the line of coincidence of the near erect image may be obtained. When so much of the intermediate zone is permitted-to become visible as corresponds to the height of the inner single image-field, both boundarylines of this single image-field are lines of coincidence, and the filling of the total surface m". -The surfaces Z and Z of the prism Z also carry silver layers, which act as separating layers. posed-in such a manner that its edge is hit by the axial ray of the pencil-system. The ray pencil system belonging to the lefthand end of the base-line and presenting the inverted image is transmitted by the reflecting prism n to theretlecting prism 0 of the separating prism system, which is con? tiguous .to the prism Z of this system in the cemented surface Z. By one part of the raypencil system belonging to the righthand end of the base-line impinging on the.

reflecting surface m and the other part on the totally reflecting surface 1*, which is inclined to m these two parts are rendered divergent. The divergence is so chosen as to cause the two" parts of the axial ray reflected by the edge of m to impinge on the edges of the cemented surface Z Hence only the two erect images, which are moved apart, are'presented 'by reflection atthe surfaces Z and V, which are inclined to each other, to the ocular, their divergence being neutralized, while the intermediate Zone with the overlapping productions of .theimages is eliminated. The place of this zone is taken in the imag the Part of the inverted image lying in the cemented Surface P.

The wedge m is dis newness For the forming'ot' the erect images, in the telemeter according to Figs ll and 12, two objective part-lenses e and 2 are em ployed, one of which 6 whichpresentsthe lower erect image has the same focal length as, the lens a, which presents the inverted image, and the other of which 6 which presents the upper erect-image has on the other hand a shorter focal length. The op tical axes ofbothpart-lenses lie parallel to each other in a plane perpendicular tothe plane of triangulation. A horizontal diaphragm 6 prevents a mixingo'f the two erect images. The separating layer 77 of the separating prism system 71,1, 7: has, as

may be seen from Fig. 13., two separating edges. The part-lens c and the lens 6 are adjusted in their position as to height in such amanner that the lower limiting line of the inner single image-field forms the line of coincidence. The axis of the partlens 0 lies so far from that of the part-lens e -that the zone of the lower erect image,

which is contiguous to the line of coincidence, is repeated inthe remote outer image field. In order to,be able to use the upper single image-field, when locating the object whose range is to be found with the telemeter, particularly well like the ima'gefield of a finder-telescope, that surface of the prism M, which carries the separating layer, is marked with a line it, delimiting in this single image-field that piece, whichcorresponds to that piece of the lower single image-field recurring in the said upper field.

In Figs. 14tto .16 the system is.- one, in which the so-called lost rays are utilized in the forming of the total image presented to the ocular. The ray-pencil-systems coming from the two ends of the base-line form two images in a separating prism system 79, 72 which contains a separating layer p",

reflecting on both sides and having an upper separating edge, on which edge the axial rays impinge, by which prism system the said two images are formed into two double images. By means of the collective lenses 9' and g and the lenses of reversion g and g these two double images are imaged in a second separating prism system g 9 to which a refiecting'prism '11 is cemented. with the help of a reflectin g prism s and the refiecting surface 9 of the prism respectively.

'Frbm the two copies of the double images two new total images are formed by the separating layer 0 in the well-known way, since it is reflecting on both sides; Each total image is derived as to one of its principal parts from one of the double images, as to itsother principal part from the other one. In both total images the magnification is thesame throughout.

One total image remains unused, while the other one, after being reflected at r, fills the image field of the ocular v1 i The separating on its separating edge, the axial ray,

layer (7 is, according to Fig. 16, so disposed that the axial ray from the one double image, which has passed through impinges however, which coming from the other double image has passed through g, is reflected at the said layer below the separating edge. The upper principal part of the total image made use of comprises the upper erect image belonging to the right-hand end of the base-line, the lower principal part comprises the lower erect image belonging to the same end and an inverted image belonging to the left-hand end, by which latter the inner single image-field is filled. The lower limiting line of the inner single imagefield, which is an image of the separatingedge of the first separating prism system 19 p the first separating edge), forms the line of coincidence. The two erect images have such a relative position as to height, that that image-line of the erect image not contiguous to the lineof coincidence, which corresponds to the image-line of the other-erect image coinciding with the line of coincidence, coincideswith the boundaryline of the first erect image. Hence the filling of the total image-field is that according to Fig. 1.

It, while retaining the disposition of the other parts as shown in Figs. 14 and 15, the separating layer 9 be limited so that the separating edge has the position shown in Fig. 17, the upper principal part of the total image made use of comprises the upper erect image and an inverted one filling the inner single image-field, the lower principal part comprising the lower erect image. In this case the upper "limiting line of the inner single image-field, which is also animage of the first separating edge, forms the line of coincidence, so that the filling of the total image-field is that according to Fig. 2. Finally, when the separating layer 9 is given the disposition according to Fig. 18, in which the separating edge has as compared with Figs. 16 and 17 an intermediate position, the total image-field will be filled as shown in Fig. 19. The inner single image-field is in this case filled by two inverted images, which are contiguous in a line parallel to the base-line. The filling of the inner single image-field is such that it would be without a gap, if the sequence, in which the two inverted images follow each other in the total image-field, were reversed. The upper principal part of the total image made use of comprises the upper erect image and the upper inverted one, which are parted by one of the images (a) of the first separating edge, the lower prin cipal part comprises the lower erect and the lower inverted image, which are parted bythe other image (o of the first separating edge. Each one of the images a and a of the first separating edge'is a line of coincidence and may optionally be used for measuring purposes.

A smaller scale and by that means an enlarged field of vision in one of the two principal parts of the total image-field made use of may e. g. be obtained, by giving to the lens ot' reversion appertaining to this part a smaller focal length than to the other one and byapproa'ching it nearer to the plane of the image-field of the ocular. -When used for the'upper principal part in a telemeter, in which the separating edge of 9 has the same position as that shown in Fig. 18, this disposition-prod fies a filling of the imagefield such as that shown in Fig. 20. Such a filling has the special advantage of providing'for the purpose of measurement two different magnifications in the same imagefield, one or the other of which may optionally be employed according to the luminosity of the object, whose range is to be found.

I claim:

In a coincidence telemetjer two objective systems, an ocular system, a measuring device and means for presenting in the field of vision of the said ocular system a total image-field comprising three single imagefields following each other in a direction perpendicular to that of the base-line, the two outer ones of which are each filled by an erect image and the inner one of which contains an image contiguous to one of the said erect images in a straight line parallel to the base-line, which straight line is a line of coincidence, these contiguous images belonging to opposite ends of the base-line and having the same magnification and'the image points 01 the erect imagecontiguous to the line of coincidence, forming this line,

being visible also in the other erect image. o'rro nrrnusrianv.

Witnesses PAUL Kniionn, RICHARD HAHN. 

